The existing stage imaging lamps are classified into halogen light source imaging lamps and LED imaging lamps according to the light sources. However, the halogen light source imaging lamp of the prior art is high in the whole lamp's heat, low in lighting efficiency, and the adjustments of the light intensity and the color temperature of which fail to be achieved. To overcome the above defects of the halogen lamp, insiders in the industry have developed an imaging lamp using LED as light source. LED lamps have been widely used in various places of entertainment due to the advantages, such as energy conservation, environmental protection, high lighting efficiency, high brightness, long working life, strong controllability, etc. In order to reduce cost and to achieve fittings sharing between LED imaging lamp and the existing imaging lamp using halogen bulb as light source, the diameter of the light spot of the focal point F of the imaging lamp is required to be between 60˜80 mm, which causes notable difficulty to the later lens design, so that many enterprises have to abandon the zoom system. Although a few enterprises have designed the zoom system, the clarity of the patterns in the zoom process is not enough to meet the usage requirements.